not(X) :- X, !, fail.
not(_).
a(X) :- b(X), write(b(X)), nl.
a(X) :- c(X), write(c(X)), nl.
b(2.0).
c(3.0).
prova_cut(X, Y) :- a(X), !, a(Y).
pippo(X, Y) :- prova_cut(X, Y).
pippo(2.0, 3.0).
